By Jan TenBruggencate
Advertiser Columnist

Oil companies on the Mainland are under siege for the use of a chemical that may reduce air pollution but can pollute groundwater.

The substance is commonly called MTBE or MtBE, which stands for methyl tertiary-butyl ether. It is refined from petroleum.

Added to gasoline, it performs wonders. It can increase octane, promote the clean burning of gasoline and reduce smog. In areas with smog problems, the Environmental Protection Agency requires petroleum firms to mix additives with their gas to reduce pollution. Some firms use MTBE. Others use ethanol, which has similar results.

Hawai'i, however, doesn't have high air pollution levels or additive requirements.

Hawai'i's major gasoline wholesalers say they're not using the compound at all, and state Health Department officials say there has never been a detected spill of the stuff or an indication it has polluted any Hawai'i groundwater.

"We do not use it here in the Islands," said Chevron representative Albert Chee.

"We don't do that," said Tesoro's Nathan Hokama.

Chevron and Tesoro both operate refineries on O'ahu.

Aloha Petroleum, a major wholesaler that buys refined gasoline, either buys locally from Chevron and Tesoro or from the Mainland. When gasoline is bought from the Mainland, it is tested to be sure it's MTBE-free, said company representative Bob Fung.

The problem with MTBE is that it is a suspected cancer-causing agent. MTBE also tastes bad. A very small amount can make water taste like paint thinner or turpentine. Some people may be able to detect the compound at as little as five parts per billion in water.

Its molecule is small, and when there is a spill on the ground, it readily migrates into the groundwater. The compound is readily soluble in water.

Articles on the subject say it gets into the groundwater faster than the other components of gasoline, stays there longer and is more difficult to clean up. It can get into the ground from leaking underground storage tanks, from spills at gas stations and from other causes, including the release of unburned fuel by two-cycle gasoline outboard motors.

"It's a major problem on the Mainland, but we're not aware of any detections here," said Bill Wong, program manager of the Department of Health's Drinking Water Branch.

States and municipalities across the Mainland — primarily ones with big cities that have air pollution problems — have sued oil companies over MTBE contamination in their water. Some states have launched legislation to ban it, and the EPA has said it is considering regulating the compound under the Toxic Substances Control Act.

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Contact him at (808) 245-3074 or e-mail jant@honoluluadvertiser.com.